Bearing isolator oil containment cup

ABSTRACT

An oil leak prevention device for use on a pump assembly having a non-contacting bearing isolator. The device has an annular surface having a central opening and a second surface extending from the first surface. The second surface covers an opening of an outside leak path between the rotor and the stator of the bearing isolator when the central opening is placed about the shaft of the pump. A method for preventing the leakage of oil from the pump assembly includes forming an oil containment cup and then placing the oil containment cup in contact with the bearing isolator such that a shaft of the pump assembly passes through the central opening and the second surface of the oil containment cup covers the opening of the leak path. Preferably, the cup is removed from the pump before operation of the pump.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to bearing isolators. Specifically, the invention relates to a disposable oil containment cup for use on a bearing isolator.

BACKGROUND OF THE INVENTION

Horizontal bearing housings are often manufactured with lip seals that seal against stainless steel sleeves fitted to the bearing housing shaft. The stainless steel sleeves are typically chromed for hardness (and thus a prolonged operating life), and then ground to have no machine lead, a necessity to prevent leakage and also extend the lip seal life. These extra steps that prevent leakage, extend the operating life of the lip seal, and protect the shaft, add considerable cost to the bearing housing assembly. Further, lip seals will typically start leaking before the bearings need to be replaced, and replacing a lip seal requires a major pump teardown.

By contrast, the bearing isolator has several advantages over the traditional bearing housing sealing solutions, including lip seals and mechanical seals in non-flooded applications. The bearing isolator is a fraction of the cost compared to a chromed and ground stainless steel sleeve. It has also been found to consume less power and, without the similar wear issues of a lip seal, last forever.

The advantages of the bearing isolator stem from the fact that they are non-contacting, meaning the rotor is not in contact with the stator. Since they are non-contacting, bearing isolators (1) lower the energy costs of the bearing housing, and (2) have no parts to wear out. Lower parasitic pump losses mean lower energy costs which will increase the overall water to wire pump efficiency, and having no parts which will wear out increases reliability.

However, a problem with bearing isolators was found to exist when horizontal pumps are shipped fully assembled and filled with oil. As the packaged pump tips due to, for example, a carrier traveling up and down hills, the bearing isolator will become flooded and oil will leak through a path between the bearing isolator rotor and stator. This is undesirable from a safety standpoint (e.g., slipping, contamination) and potentially catastrophic if oil loss is undetected and enough is leaked from the assembly to cause premature bearing failure.

Until the invention of the present application, this problem was solved in other ways by those skilled in the art. The present oil containment cup provides an inexpensive solution which functions to prevent oil leakage during shipment of assembled pump systems having bearing isolators without sacrificing reliability or efficiency.

SUMMARY OF THE INVENTION

There is disclosed herein improved unique oil leak prevention device and method for a pump assembly which affords cost and operating advantages.

Generally speaking, the oil leak prevention device is for use on a horizontal pump assembly having a non-contacting bearing isolator. The device comprises a first annular surface having an inner edge defining a central opening and a second surface extending from an outer edge of the first surface. The second surface is configured to cover an outside leak path between the rotor and the stator of the non-contacting bearing isolator when the central opening is placed about the shaft of the pump.

In specific alternate embodiments, the second surface may extend from only a portion of the first surface or from the entire first surface. Likewise, the first surface may be a complete annular ring or a partial ring. Preferably, the second surface is normal (i.e., perpendicular) to the first surface.

In preferred embodiments, the first and second surfaces are comprised of a synthetic, oil-resistant, elastomeric material, such as nitrile rubber, fluoroelastomers (e.g., VITON®) or similar elastomeric material, for a good fit on the bearing isolator and resistance to typical oils.

As for the disclosed method for preventing the leakage of oil from a pump assembly having at least one bearing isolator comprising a stator, a rotor and a leak path between the rotor and stator, the leak path having an opening outside a bearing housing of the pump assembly, the method comprises the steps of first forming an oil containment cup having a first annular surface with an inner edge defining a central opening, and a second surface extending from an outer edge of the first surface, and then placing the oil containment cup in contact with the bearing isolator such that a shaft of the pump assembly passes through the central opening and the second surface of the oil containment cup covers the opening of the leak path. Preferably, the cup is removed from the pump before operation of the pump.

These and other aspects of the invention may be understood more readily from the following description and the appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of facilitating an understanding of the subject matter sought to be protected, there are illustrated in the accompanying drawings, embodiments thereof, from an inspection of which, when considered in connection with the following description, the subject matter sought to be protected, its construction and operation, and many of its advantages should be readily understood and appreciated.

FIG. 1 is a cross section of bearing isolators installed in a bearing housing for a chopper pump assembly;

FIG. 2 is a cross section of a bearing isolator showing the outside leak path between the rotor and the stator;

FIG. 3 is a perspective view of an embodiment of an oil containment cup installed on a bearing isolator;

FIG. 4 is a cross section of a bearing isolator with an installed oil containment cup;

FIG. 5 is a front view of an embodiment of the oil containment cup shown in FIG. 3;

FIG. 6 is a cross section of the oil containment cup of FIG. 5;

FIG. 7 is a front view of an alternate embodiment of the oil containment cup; and

FIG. 8 is a cross section of the alternate embodiment of FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail at least one preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspect of the invention to any of the specific embodiments illustrated.

Referring to FIGS. 1-8, there is illustrated a bearing housing 10 having first and second bearing isolators 12, and an oil containment cup generally designated by the numeral 14 attached to a bearing isolator 12. The particular illustrated containment cup 14 is for use during shipping of a horizontal chopper pump system (not shown). However, it should be understood that the principles of the invention may be more broadly applied to other pump systems, as well as other types of systems which use bearing housings and bearing isolators.

As can be seen in FIG. 1, the bearing housing 10, when filled, has an oil level just below the lowest drain back level. This poses no problems while the chopper pump assembly is maintained in a level horizontal position. However, during shipment of the chopper pump assembly, the freight may experience periods of being unlevel (due to hills and the like) which may cause the lowest drain back level at either end of the bearing housing 10 to fall below the oil level. As a result, the oil will enter the outside leak path 18 between the rotor 15 and stator 17 and exit at the opening 19. Obviously, this is a very undesirable result.

Accordingly, as shown in FIGS. 3 and 4, an oil containment cup 14 has been devised to engage the bearing isolator 12 and block the opening 19 of the outside leak path 18. Each bearing housing 10 has a vent on top to allow the bearing housing 10 to “breathe”, so there is no benefit in providing a permanent, extra seal in the bearing isolator 12. The oil containment cup 14 is only to stop oil leakage from occurring during shipping and handling. The L-shaped oil containment cup 14 is designed to be cut away by the user just prior to pump startup; it is not intended to be used as part of the installed, rotating equipment, though a user who does not follow directions could end up doing this. If no oil ever gets onto the surfaces of the oil containment cup 14, the friction heat from running would likely cause the cup 14 to overheat and break away eventually. However, if oil is on the oil containment cup 14 from the pump being tipped out of horizontal during shipping or handling, that lubrication might be enough to keep the cup 14 from overheating.

As shown in FIGS. 5 and 6, the preferred cup 14 has an L-shaped cross section with first (i.e., positioning) surface 20 and second (i.e., containment) surface 22 forming a right angle. An inside edge 24 of the first surface 20 defines a central opening 26 which allows the cup 14 to fit over the shaft 16 of the pump system. The first surface 20 fits flush to the rotor 15 of the bearing isolator 12, while the second surface 22 extends perpendicularly to cover the opening 19 of the leak path 18 on the bearing isolator 12 (see FIG. 4).

In an alternate embodiment, only the containment surface 22 may be used to form an oil containment device. The device, similar to an elastic band, could be tension fit to the bearing isolator to cover the opening 19 with the containment surface 22. The positioning surface (i.e., first surface 20 in above embodiment) allows the containment cup to be more easily positioned and installed on the isolator.

Preferably, the cup 14 is made of a synthetic, oil-resistant, elastomeric material, such as nitrile rubber, fluoroelastomers (e.g., VITON®) or similar material, for a good fit on the bearing isolator and resistance to typical oils. The thickness of the first surface 20 and the second surface 22 is preferably about 0.040 inches (about 0.10 cm) using nitrile rubber material. The thickness may vary, of course, based on the diameter of the bearing isolator. The material is also preferably red in color to stand out from the other components of the pump system, and red is typically the color for warning labels. Other materials, colors and alternate thicknesses may also be suitable.

In alternate embodiments, the first surface 20 may comprise less than a full ring, as illustrated in FIG. 7. As shown, the first surface 20 has an open side 30 which may allow easier installation of the cup 14 onto the bearing isolator 12, but still enough surface to maintain good contact with the rotor 15. Likewise, the second surface 22 may only extend from a portion of the first surface 20 (whether a full or partial ring), as shown in FIG. 8. The width of the second surface 22 need only be large enough to cover the opening 19 of the leak path 18. Variations of these two designs are certainly possible.

The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only and not as a limitation. While particular embodiments have been shown and described, it will be apparent to those skilled in the art that changes and modifications may be made without departing from the broader aspects of applicants' contribution. The actual scope of the protection sought is intended to be defined in the following claims when viewed in their proper perspective based on the prior art. 

1. An oil leak prevention device for a horizontal chopper pump having a non-contacting bearing isolator, the device comprising: a first annular surface having an inner edge defining a central opening; and a second surface extending from an outer edge of the first surface; wherein the second surface is configured to cover an outside leak path between the rotor and the stator of the non-contacting bearing isolator when the central opening is placed about the shaft of the pump.
 2. The oil leak prevention device of claim 1, wherein the second surface is normal to the first surface.
 3. The oil leak prevention device of claim 1, wherein the second surface extends from a portion of the first surface.
 4. The oil leak prevention device of claim 1, wherein the second surface extends from the entire circumference of the first surface.
 5. The oil leak prevention device of claim 1, wherein the first surface forms a complete ring.
 6. The oil leak prevention device of claim 1, wherein the first surface forms a partial ring.
 7. The oil leak prevention device of claim 1, wherein the first surface and second surface are comprised of an oil-resistant elastomer.
 8. A device for preventing leakage of oil from a pump assembly having at least one bearing isolator comprising a stator, a rotor and an outside leak path between the rotor and stator, the device comprising: a first annular surface having an inner edge defining a central opening, the surface being comprised of an oil-resistant, elastomeric material; and a second surface extending substantially perpendicularly from at least a portion of an outer edge of the first surface, the second surface being comprised of an oil-resistant elastomeric material; wherein the second surface is configured to cover an outside leak path opening between the rotor and the stator of the non-contacting bearing isolator when the central opening is placed about the shaft of the pump and the first surface contacts the rotor.
 9. The device of claim 8, wherein the first surface forms a complete annular ring.
 10. A method for preventing the leakage of oil from a pump assembly having at least one bearing isolator comprising a stator, a rotor and a leak path between the rotor and stator, the leak path having an opening outside a bearing housing of the pump assembly, the method comprising the steps of: forming an oil containment device having a containment surface sufficient for covering the entire opening of the leak path; and placing the oil containment device in contact with the bearing isolator such that the containment surface of the oil containment device covers the opening of the leak path.
 11. The method of claim 10, wherein the oil containment device comprises a positioning surface extending from the containment surface.
 12. The method of claim 11, wherein the positioning surface is normal to the containment surface.
 13. The method of claim 12, wherein the containment surface extends from a portion of the positioning surface.
 14. The method of claim 12, wherein the containment surface extends from the entire circumference of the positioning surface.
 15. The method of claim 11, wherein the positioning surface forms a complete ring.
 16. The method of claim 11, wherein the positioning surface forms a partial ring.
 17. The method of claim 10, further comprising the step of removing the oil containment device before operation of the pump.
 18. The method of claim 10, wherein the oil containment device is formed of nitrile rubber.
 19. The method of claim 10, wherein the oil containment device is formed of fluoroelastomeric material. 